JP7073304B2 - Shock absorption mechanism - Google Patents

Description

The present invention relates to a shock absorbing mechanism that absorbs a shock applied to a vehicle.

Patent Documents 1 and 2 describe techniques relating to an impact absorbing mechanism configured to receive an impact load at the time of a vehicle collision and absorb the impact.

According to Patent Documents 1 and 2, when the bumper shear is pushed toward the side member during a vehicle front collision, the wood provided between the bumper shear and the side member is pushed by a connecting material such as a bolt and is pushed in the member axial direction. A shock absorbing mechanism is described in which a shock is absorbed by compression or shearing in the wood in the axial direction of the member.

International Publication No. 2014/077314 Japanese Unexamined Patent Publication No. 2017-7598

These shock absorbing mechanisms absorb the shock when the wood is compressed or sheared in the axial direction of the member, but such a shock absorbing mechanism absorbs the shock more effectively and causes damage in the event of a vehicle collision. Ingenuity that can be reduced is required.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a shock absorbing mechanism capable of more effectively absorbing shocks.

The first invention for achieving the above-mentioned object is a shock absorbing mechanism for reducing the impact load applied to the vehicle, and the load receiving member that receives the impact load and the impact load are transmitted from the load receiving member. A wooden columnar impact absorbing material provided between the members to be transmitted and having one end in the axial direction of the member inserted into the internal space of the load receiving member and one of the members to be transmitted, and the above. A first connecting material that is connected to one member and presses the impact absorbing material at the time of collision is provided, and the shock absorbing material is pushed against the first connecting material at the time of collision, and the first connecting material is pressed. The impact absorbing material enters the space on the side perpendicular to the member axis, and the width of the first connecting member along the member axis orthogonal direction is 2D ₁ , the load receiving member and the transmitted object. The member that passes through the center of the cross section of the first connecting member along the axial direction of the member, where the width of the flat surface portion or the concave surface portion of the _first connecting member facing the other member side of the member is 2C1. The distance X ₁ between the center line of the cross section in the axial direction and the side surface of the impact absorbing material closer to the first connecting member is X ₁ ≤ {D ₁ − (1-ε) C ₁ } / ε. In the stress-strain distribution showing the relationship between stress and strain when the impact absorbing material is compressed in the direction perpendicular to the member axis, ε is defined by It is a shock absorbing mechanism characterized by having a strain value corresponding to a strain hardening region in which the rigidity of the impact absorbing material increases again after the rigidity of the impact absorbing material decreases.

The second invention is a shock absorbing mechanism for reducing a collision load applied to a vehicle, which is provided between a load receiving member that receives a collision load and a transmitted member to which the collision load is transmitted from the load receiving member. One end in the axial direction of the member is connected to the wooden columnar shock absorber inserted into the internal space of the load receiving member and one of the members to be transmitted, and collides with the one member. A plurality of first connecting materials that sometimes press the shock absorbing material are provided, and the shock absorbing material is pushed by the first connecting material at the time of collision, and the shock absorbing material is viewed from the first connecting material. Enter the space on the side of the member axis orthogonal to the member axis, set the width of the first connecting member along the member axis orthogonal direction to 2D ₁ , the other member of the load receiving member and the transmitted member. The width of the flat surface portion or the concave surface portion of the first connecting material facing the side is 2C ₁ , and the cross-sectional center line in the member axial direction passing through the center of the cross section of the first connecting material along the member axial direction. And the distance X ₁ between the adjacent first connecting member and the line segment in the axial direction of the member that divides the first connecting member into two equal parts is X ₁ ≤ {D ₁ − (1-ε) C ₁ } / ε. In the stress-strain distribution showing the relationship between stress and strain when the shock absorber is compressed in the direction perpendicular to the member axis, ε is defined by It is a shock absorbing mechanism characterized by having a strain value corresponding to a strain hardening region in which the rigidity of the shock absorbing material increases again after the rigidity of the shock absorbing material decreases.

In the present invention, the distance between the connecting material and the side surface of the shock absorbing material (first invention) and the distance between adjacent connecting materials (second invention) are determined as described above when the shock absorbing material is compressed. It shall be less than or equal to the predetermined value determined based on the strain value ε. By narrowing these distances in this way, the path of the shock absorbing material pushed by the connecting material at the time of collision is narrowed, and the shock absorbing material is hardened by the compression generated in the direction orthogonal to the member axis, and a high shock absorbing effect is obtained. It is possible to effectively absorb shocks with a simple configuration that only sets the position of the connecting material appropriately.

It is also desirable that the cross section of the first connecting member is substantially circular and the distance X ₁ is determined by X ₁ ≤ D ₁ / ε with C ₁ = 0.
When a member having a circular cross section such as a normal bolt is used as the connecting material, C ₁ = 0 and the distance X ₁ may be D ₁ / ε or less. By making the cross section of the connecting material circular, the shock absorbing material is likely to be pushed separately, and the above-mentioned shock absorbing effect is easily exerted.

The first connecting material is abutted against, for example, the end face of the shock absorbing material. Alternatively, the first connecting material may penetrate the shock absorbing material.
In the former case, there is no need to make a hole in the shock absorbing material, and the structure is simple. In the latter case, the impact absorbing material can be suitably held by the connecting material.

The other end of the shock absorber in the axial direction of the member is inserted into the internal space of the other member, connected to the other member, and a plurality of second connections that press the shock absorber in the event of a collision. The first and second connecting materials are further provided with materials, and the first and second connecting materials are arranged at different positions when viewed from the axial direction of the member. Entering the space on the side in the direction orthogonal to the member axis when viewed from the connecting member of 2, the width of the second connecting material along the direction perpendicular to the member axis is 2D ₂ and faces the one member side. The width of the flat surface portion or the concave surface portion of the second connecting member is 2C ₂ , and the width thereof is adjacent to the cross-sectional center line in the member axial direction passing through the center of the cross section of the second connecting member along the member axial direction. The distance X ₂ between the member axial line segment that divides the second connecting member into two equal parts is determined by X ₂ ≦ {D _2- (1-ε) C ₂ } / ε. Is also desirable.
In this case, shock absorption by shearing in the member axial direction of the shock absorbing material becomes possible, but in this case as well, by narrowing the path of the shock absorbing material pushed by the connecting material at the time of collision as described above, the member axis is orthogonal to each other. The shock absorbing material is hardened by the compression generated in the direction, and a high shock absorbing effect can be obtained.

According to the present invention, it is possible to provide a shock absorbing mechanism capable of more effectively absorbing shocks.

The schematic which shows the arrangement of the shock absorption mechanism 2. The figure which shows the shock absorption mechanism 2. The figure which shows the outline of the stress-strain distribution. The figure which shows the shock absorption mechanism 2 in the state which the collision load is applied. The figure which shows the relationship between the displacement of a bumper reinforce 11 and the load absorbed by the compression of a shock absorbing material 1. An example of a flat surface portion 5 and a concave surface portion 6. The figure which shows the shock absorption mechanism 2'. The figure which shows the shock absorption mechanism 2a. The figure which shows the shock absorption mechanism 2a in the state which the collision load is applied. The figure which shows the shock absorption mechanism 2b. The figure which shows the shock absorption mechanism 2c. The figure which shows the shock absorption mechanism 2c in the state which the collision load is applied. The figure which shows the shock absorption mechanism 2c'. The figure which shows the shock absorption mechanism 2d. The figure which shows the shock absorption mechanism 2d in the state which the collision load is applied.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic view showing an arrangement of a shock absorbing mechanism 2 according to an embodiment of the present invention. The impact absorbing mechanism 2 is provided on the vehicle 10 and is for absorbing the impact applied to the vehicle 10 at the time of a collision to reduce the collision load. The shock absorbing mechanism 2 is arranged between the bumper reinforce 11 of the front bumper (not shown) and the side member 9 of the vehicle 10.

The left and right sides of FIG. 1 correspond to the front-rear direction of the vehicle, and the top and bottom of FIG. 1 correspond to the width direction of the vehicle. Hereinafter, the term "front" refers to the front side of the vehicle 10 and corresponds to the left side of FIG. "Rear" refers to the rear side of the vehicle 10 and corresponds to the right side of FIG.

The bumper reinforce 11 is a load receiving member that receives a collision load at the time of a frontal collision of the vehicle, and is arranged so as to extend in the vehicle width direction at the front portion of the vehicle 10.

The side member 9 is a transmitted member to which the collision load received by the bumper reinforce 11 is transmitted. The side members 9 are arranged on the left and right in the vehicle width direction, and a shock absorbing mechanism 2 is provided between each side member 9 and the bumper reinforcement 11.

FIG. 2 is a diagram showing a shock absorbing mechanism 2. FIG. 2A is a diagram showing a horizontal cross section of the shock absorbing mechanism 2, and FIG. 2B is a diagram showing a vertical cross section along the line aa of FIG. 2A.

As shown in FIG. 2, the shock absorbing mechanism 2 has a shock absorbing material 1, a bolt 3, and the like.

The shock absorbing material 1 is a wooden columnar member, and the member axial direction is the vehicle front-rear direction (corresponding to the left-right directions of FIGS. , Arranged so as to be on the side member 9 side. In the present embodiment, the axial direction of the member of the shock absorbing material 1 corresponds to the axial direction of the annual ring of the wood (the fiber direction of the wood), but the present invention is not limited to this.

The front end portion of the shock absorbing material 1 abuts on the bumper reinforce 11 and is fixed to the bumper reinforce 11 by the bracket 13.

The front end portion of the side member 9 has a cylindrical shape, and the rear end portion (one end portion) of the shock absorbing material 1 is inserted into the internal space of the tubular portion of the side member 9 (one member).

The bolt 3 is a metal headed bolt, and is arranged behind the shock absorbing material 1 against the rear end surface of the shock absorbing material 1. The bolt 3 is a rod-shaped connecting member connected to the front end portion of the side member 9, and presses the shock absorbing material 1 forward at the time of a collision. The bolts 3 are arranged so that the longitudinal direction is aligned with the vertical direction (corresponding to the vertical direction in FIG. 2B), and a plurality of bolts 3 are provided in the vehicle width direction. The vehicle width direction corresponds to the vertical direction of FIG. 2A, and is a member axis orthogonal direction orthogonal to the member axis direction of the shock absorber 1. In the example of the figure, two bolts 3 are arranged, but the number of the bolts 3 is not particularly limited, and only one bolt may be used.

Here, when viewed from the member axial direction of the shock absorber 1 (see the arrow in FIG. 2A), the side between the bolt 3 and the bumper reinforce 11 (the other member) is located at a position overlapping with the bolt 3. There is no other bolt 3 or the like connected to the member 9, and this bolt 3 greatly contributes to shock absorption.

The shaft portion of the bolt 3 penetrates the side member 9 from the lower surface of the side member 9, and the tip of the shaft portion is fixed to the upper surface of the side member 9 by the nut 4. As a result, the bolt 3 is connected and fixed to the front end portion of the side member 9.

A flat surface portion 5 facing the bumper reinforce 11 side is formed at the central portion of the shaft portion of the bolt 3 in the vehicle width direction. In the present embodiment, the cross section of the bolt 3 along the member axial direction of the shock absorbing material 1 (hereinafter, may be simply referred to as a cross section) has a substantially regular hexagonal shape, and the flat surface portion 5 corresponds to one side thereof. Inclined surfaces inclined with respect to the member axial direction are formed on both sides of the flat surface portion 5. The flat surface portion 5 is formed by processing the shaft portion of the bolt 3, but is not limited to this. For example, another component having the flat surface portion 5 may be separately attached to the shaft portion of the bolt.

In the shock absorbing mechanism 2, when the width (maximum width) of the bolt 3 along the vehicle width direction is 2D ₁ and the width of the flat surface portion 5 is 2C ₁ , the cross-sectional center line in the member axial direction passing through the cross-sectional center of the bolt 3 The distance X ₁ between L and the side surface of the shock absorber 1 closer to the bolt 3 is {D ₁ − (1-ε) C ₁ } / ε or less. In this embodiment, the side surface of the shock absorbing material 1 is in contact with the inner surface of the side member 9.

Here, ε is a value determined by the strain when the shock absorber 1 is compressed in the vehicle width direction. As shown in FIG. 3A, the strain means the ratio of the decrease in the width of the impact absorbing material 1 due to compression to the original width.

FIG. 3B is a diagram showing an outline of a stress-strain distribution showing the relationship between stress and strain when wood (impact absorber 1) is compressed in the vehicle width direction. As shown in the figure, in the elastic deformation region of wood, the strain increases linearly as the stress increases, and after reaching the maximum strain value ε ₀ in the elastic deformation region, the rigidity of the wood decreases. Strain progresses with the stress being almost constant. This area is the plateau area, and after the maximum strain value ε ₁ in the plateau area is reached, the wood becomes a strain hardening area where the wood hardens and the rigidity rises again (for example, Tanahashi, Ooka, Ituno, Suzuki "Wood digging". Formulation of yield mechanism and uniform elasto-plastic displacement ”, Proceedings of the Structural Society of Japan, Vol.76, No.662, pp.811-819, Liu, Norimoto, Shikaoka“ Large lateral compression deformation of wood (II) ) Stress-Strain Repeat Diagram ”, Wood Research and Materials, No.31, 44-55, etc.).

In the present embodiment, the above-mentioned ε is set to the above-mentioned ε ₁ or more, and is a value corresponding to the strain hardening region. For example, the strain value in the strain hardening region as shown by ε in FIG. 3 (b) and the maximum strain value in which the strain hardly increases even if the stress increases as shown by ε'are used. These values are obtained, for example, by performing a compression test as shown in the above-mentioned document in advance under the conditions reflecting the usage state of the shock absorbing mechanism 2 shown in FIG. 2 and the like. Alternatively, a known value may be used depending on the type of wood.

FIG. 4 is a diagram showing a shock absorbing mechanism 2 in a state where a collision load is applied. FIG. 4A shows a horizontal cross section of the shock absorbing mechanism 2, and FIG. 4B shows an enlarged view of the vicinity of the bolt 3.

In the shock absorbing mechanism 2, when a collision load is applied in the direction indicated by the arrow A in FIG. 4A and the bumper reinforcement 11 is pushed toward the side member 9, the bolt 3 pushes the shock absorbing material 1 forward and the bolt 3 In the portion corresponding to the flat surface portion 5, the shock absorbing material 1 is compressed in the axial direction of the member, the wood is hardened, and the compressed portion 15a is formed. On the other hand, in the portion corresponding to the inclined surfaces on both sides of the flat surface portion 5, the shock absorbing material 1 is pushed apart as shown by the arrow B in FIG. Enter into member 9.

At this time, the shock absorbing material 1 pushed by the bolt 3 passes through a narrow space between the bolt 3 and the side member 9, and is compressed in the vehicle width direction in the space, the wood is hardened, and the compressed portion 15 is formed. To.

Considering the portion of the shock absorber 1 that is pushed apart by the bolt 3 and passes between the bolt 3 and the side member 9, with reference to FIG. 4B, the flat surface portion of the bolt 3 before being pushed by the bolt 3 The impact absorber 1 in the width range (X1 _- C ₁ ) between the 5 and the side surface of the impact absorber 1 is compressed in the vehicle width direction as it passes between the bolt 3 and the side member 9, and has a width. It becomes (X1 _{- D1} ).

At this time, the ratio (D1 _- C ₁ ) / (X _1- ) of the decrease in the width of the shock absorber ₁ due to the compression in the vehicle width direction to the original width (X _{1 -} C ₁ ). When C ₁ ) is ε or more, the wood is hardened by compression in the vehicle width direction, and a high impact absorption effect can be obtained.

That is, if the following equation (1) holds for the distance X ₁ , the impact absorber 1 is sufficiently compressed in the vehicle width direction, a strain hardening phenomenon occurs, and the collision load is absorbed.
X ₁ ≤ {D _1- (1-ε) C ₁ } / ε ... (1)

In FIG. 5, the relationship between the displacement of the bumper reinforce 11 in the above collision process and the load absorbed by the compression of the impact absorbing material 1 is defined as the vertical axis as the load and the horizontal axis as the displacement of the bumper reinforce 11 toward the side member 9. It is a figure shown.

The solid line 19 is a case where the distance X ₁ is {D ₁ − (1-ε) C ₁ } / ε or less as in the present embodiment. In this embodiment, in addition to the compression portion 15a, the shock absorber 1 Is pushed by the bolt 3 and enters the narrow space between the bolt 3 and the side member 9. At this time, the shock absorber 1 is compressed in the vehicle width direction to form the compression portion 15, so that immediately after the collision. It can stably receive a large load.

On the other hand, the dotted line 17 is a case where the distance X ₁ is larger than {D ₁ − (1-ε) C ₁ } / ε, and the impact absorbing material pushed by the bolt 3 and entered between the bolt 3 and the side member 9. 1 is not sufficiently compressed, and the displacement proceeds with a lower load than the example of the solid line 19. The impact absorption amount of the impact absorber 1 is represented by an integrated value of the load due to displacement, and in the impact absorption mechanism 2 shown by the solid line 19, the impact absorption amount is significantly increased as compared with the example shown by the dotted line 17.

As described above, in the first embodiment, the distance X1 between the bolt 3 and the side surface of the shock absorber ₁ is the above-mentioned when the shock absorber is compressed in the vehicle width direction as in the equation (1). It shall be less than or equal to the predetermined value determined based on the strain value ε. By narrowing these intervals in this way, the path of the shock absorbing material 1 pushed by the bolt 3 at the time of a collision is narrowed, and the shock absorbing material 1 is hardened by the compression generated in the vehicle width direction, and a high shock absorbing effect can be obtained. In the present embodiment, shock absorption can be effectively performed with a simple configuration in which the position of the bolt 3 is appropriately set, and the process and cost do not increase.

However, the present invention is not limited to this. For example, in the present embodiment, the metal bolt 3 is used as the connecting material, but the connecting material may be any material connected to the side member 9, and may be a pin or the like as well as a bolt. The material is not limited to metal, but may be ceramic or the like.

Further, the cross-sectional shape of the connecting material is not particularly limited. For example, as shown in FIG. 6A, a part of the circle may be cut out by a straight line, and in this case, the straight line portion becomes the flat surface portion 5. In addition, it is also possible to make the cross section pentagonal, or to make the straight line portion a flat surface portion 5 as a heptagon or more polygonal shape.

Alternatively, a concave surface portion may be provided instead of the flat surface portion 5, and the concave surface portion 6 can be provided as a cross-sectional shape obtained by cutting a part of a circle with an arc as shown in FIG. 6 (b), for example. Further, the concave surface portion 6 is not limited to an arc shape, and may be provided with a concave surface portion 6 formed in a wedge shape by a straight line, for example, having a cross-sectional shape obtained by cutting a part of a circle into a wedge shape as shown in FIG. 6 (c). In this case, as illustrated in FIG. 6B, the width 2C ₁ described above may be the width of the concave surface portion 6.

Further, as shown in the shock absorbing mechanism 2'in FIG. 7 (a), the shock absorbing material 1 may be covered with the covering material 1a. In the shock absorbing mechanism 2', the entire surface of the shock absorbing material 1 is covered with a covering material 1a such as resin, and the shock absorbing material 1 is protected from the outside world. Also in this case, as shown in FIG. 7B, the distance X ₁ is defined as the distance between the cross-sectional center line L of the bolt 3 and the side surface of the impact absorber 1 closer to the bolt 3, and the above equation ( The position of the bolt 3 can be set by 1).

Hereinafter, another example of the present invention will be described as the second to fifth embodiments. The differences between the embodiments and the embodiments described so far will be described, and the same configurations will be omitted with reference to the same reference numerals in the drawings and the like. Further, the configurations described in each embodiment including the first embodiment can be combined as necessary.

[Second Embodiment]
FIG. 8 is a diagram showing a shock absorbing mechanism 2a according to a second embodiment of the present invention. The shock absorbing mechanism 2a is mainly different from the first embodiment in that the cross section of the bolt 3a is substantially circular and does not have the flat surface portion 5 or the concave surface portion 6.

FIG. 9 is a diagram showing a shock absorbing mechanism 2a in a state where a collision load is applied. FIG. 9A shows a horizontal cross section of the shock absorbing mechanism 2a, and FIG. 9B shows an enlarged view of the vicinity of the bolt 3a.

In the shock absorbing mechanism 2a, when a collision load is applied in the direction indicated by the arrow A in FIG. 9A and the bumper reinforce 11 is pushed toward the side member 9, the bolt 3a pushes the shock absorbing material 1 forward to absorb the shock. The material 1 is pushed apart as shown by the arrow B in FIG. 9B on both sides of the cross-sectional center line L of the bolt 3a, and enters the side member 9 from the space on the side in the vehicle width direction when viewed from the bolt 3a. ..

At this time, the impact absorbing material 1 pushed by the bolt 3a passes through a narrow space between the bolt 3a and the side member 9, and is compressed in the vehicle width direction in the space, the wood is hardened, and the compressed portion 15 is formed. To.

With reference to FIG. 9B, considering the portion of the shock absorber 1 that is pushed apart by the bolt 3a and passes between the bolt 3a and the side member 9, the center of the cross section of the bolt 3a before being pushed by the bolt 3a. The impact absorber 1 in the range of width X ₁ between the wire L and the side surface of the impact absorber 1 is compressed in the vehicle width direction as it passes between the bolt 3a and the side member 9, and the width (X ₁ − It becomes D ₁ ).

At this time, if the ratio of the decrease in the width of the shock absorber ₁ due to the compression in the vehicle width direction to the original width X ₁ of D ₁ is ε or _more , the wood is hardened by the compression in the vehicle width direction. High shock absorption effect can be obtained.

That is, if the following equation (2) holds for the distance X ₁ , the impact absorber 1 is sufficiently compressed in the vehicle width direction, a strain hardening phenomenon occurs, and the collision load is absorbed, as in the first embodiment. The effect of is obtained. Further, in the present embodiment, since the cross section of the bolt 3a is circular, the impact absorbing material 1 can be easily pushed separately, and the above-mentioned impact absorbing effect can be easily exerted.
X ₁ ≤ D ₁ / ε ... (2)

The equation (2) is equivalent to the equation (1) in which C ₁ = 0. That is, the above equation (1) is an equation that can be applied even when C ₁ = 0 and there is no flat surface portion 5 or concave surface portion 6 on the bolt 3a as in the present embodiment (C ₁ = 0). There is.

[Third Embodiment]
FIG. 10 is a diagram showing a shock absorbing mechanism 2b according to a third embodiment of the present invention. The shock absorbing mechanism 2b is mainly different from the second embodiment in that the bolt 3a is provided so as to penetrate the shock absorbing material 1.

Even when the bolt 3a penetrates the impact absorbing material 1 in this way, the same effect as that of the first embodiment can be obtained by determining the position of the bolt 3a by the above formula (2). Further, since the bolt 3a penetrates the shock absorbing material 1, the shock absorbing material 1 can be suitably held by the bolt 3a. On the other hand, when the bolt 3a is abutted against the end face of the impact absorbing material 1 as in the second embodiment, it is not necessary to make a hole in the impact absorbing material 1 and the structure is simple.

In addition, instead of the bolt 3a, the bolt 3 having the flat surface portion 5 as in the first embodiment may be arranged so as to penetrate the impact absorbing material 1. In this case, the bolt 3 may be arranged by the above formula (1). You just have to determine the position of.

[Fourth Embodiment]
FIG. 11 is a diagram showing a shock absorbing mechanism 2c according to a fourth embodiment of the present invention. In this shock absorbing mechanism 2c, the distance X1 between the cross _- sectional center line L of the bolt 3a and the line segment La in the axial direction of the member that bisects between the adjacent bolts 3a is determined by the above equation (2). It differs mainly from the second embodiment in that it is different from the second embodiment.

FIG. 12 is a diagram showing a shock absorbing mechanism 2c in a state where a collision load is applied. FIG. 12A shows a horizontal cross section of the shock absorbing mechanism 2c, and FIG. 12B shows an enlarged view of the vicinity of the bolt 3a.

In the shock absorbing mechanism 2c, when a collision load is applied in the direction indicated by the arrow A in FIG. 12A and the bumper reinforce 11 is pushed toward the side member 9, each bolt 3a pushes the shock absorbing material 1 forward and impacts. The absorbent material 1 is pushed separately on both sides of the cross-sectional center line L of each bolt 3a as shown by the arrow B in FIG. Enter into.

At this time, the impact absorbing material 1 pushed by the bolts 3a passes through a narrow space between the bolts 3a and is compressed in the vehicle width direction in the space, and the wood is hardened to form the compressed portion 15.

Considering the portion of the shock absorbing material 1 that is pushed by the bolt 3a and passes between the two bolts 3a with reference to FIG. 12B, the cross-sectional center line L of both bolts 3a before being pushed by the bolt 3a. When the shock absorber 1 in the range of the width _{2 × 1 is compressed in the vehicle width direction when passing between the bolts 3a, the width (2X 1-2D 1 ) is} obtained.

At this time, if the ratio of the decrease in the width of the shock absorber ₁ due to the compression in the vehicle width direction to the original width 2X ₁ of 2D ₁ is ε or _more , the wood is hardened by the compression in the vehicle width direction. High shock absorption effect can be obtained.

That is, if the following equation (2') holds for the distance X ₁ , the impact absorber 1 is sufficiently compressed in the vehicle width direction, a strain hardening phenomenon occurs, and the collision load is absorbed, as in the first embodiment. A similar effect can be obtained. This equation (2') is the same as the above equation (2).
X ₁ ≤ D ₁ / ε ... (2')

This also applies to the case where the bolt 3 having the flat surface portion 5 is used as shown in the impact absorption mechanism 2c'in FIG. 13, and in this case, the position of the bolt 3 may be determined by the above equation (1). ..

At the same time as setting the distance between the bolts in this way, the distance between the bolts and the side surface of the shock absorbing material 1 is also determined as described in the first and second embodiments, so that the distance between the bolts and the distance between the bolts can be determined. It is also possible to simultaneously generate a shock absorbing effect by compressing the shock absorbing material 1 between the bolt and the side member 9.

[Fifth Embodiment]
FIG. 14 is a diagram showing a shock absorbing mechanism 2d according to a fifth embodiment of the present invention. 14 (a) is a diagram showing a horizontal cross section of the shock absorbing mechanism 2d, and FIGS. 14 (b) and 14 (c) are vertical along the lines bb and cc of FIG. 14 (a), respectively. It is a figure which shows the cross section in the direction.

This shock absorbing mechanism 2d is mainly different from the first embodiment in that shock absorbing by shearing of the shock absorbing material 1 is performed. That is, in the shock absorbing mechanism 2d, the front end portion (the other end portion) of the shock absorbing material 1 is inserted into the internal space of the bumper reinforce 11a (the other member) from the opening 110 provided in the rear wall of the tubular bumper reinforce 11a. Will be inserted.

The shock absorbing mechanism 2d has a bolt 3 connected to the bumper reinforce 11a in addition to the configuration of the shock absorbing mechanism 2 of the first embodiment. The shaft portion of the bolt 3 penetrates the bumper reinforce 11a from the lower surface of the bumper reinforce 11a, and the tip of the shaft portion is fixed to the upper surface of the bumper reinforce 11a by the nut 4. The bolt 3 is arranged so as to abut against the front end surface of the shock absorbing material 1 and has a flat surface portion 5 facing the side member 9.

Here, when viewed from the member axial direction (see the arrow in FIG. 14A), the bolt 3 at the front end portion and the bolt 3 at the rear end portion of the impact absorbing material 1 are arranged at different positions. Further, when viewed from the member axial direction, between the bolt 3 at the front end of the shock absorber 1 and the side member 9, another bolt 3 or the like connected to the bumper reinforce 11a is located at a position overlapping the bolt 3 at the front end. not exist.

An opening 111 is formed on the front wall of the bumper reinforce 11a at a position corresponding to the bolt 3 at the rear end of the shock absorbing material 1 in the vehicle width direction.

The bolt 3 at the rear end of the shock absorbing material ₁ has the same distance X1 between the cross-sectional center line L of the bolt 3 and the side surface of the shock absorbing material 1 closer to the bolt 3 as in the first embodiment. It is stipulated in.

On the other hand, for the bolt 3 at the front end of the shock absorbing material 1, the distance X ₂ between the cross-sectional center line L of the bolt 3 and the line segment La in the member axial direction that bisects between the adjacent bolts 3 is shown in FIG. Etc., it is determined to be {D _2- (1-ε) C ₂ } / ε or less by the equation (1). Here, the width of the bolt 3 at the front end portion of the shock absorbing material 1 is 2D ₂ , and the width of the flat surface portion 5 thereof is 2D ₂ .

In the shock absorbing mechanism 2d, when a collision load is applied in the direction shown by the arrow A in FIG. 15 and the bumper shear 11a is pushed toward the side member 9, the bolt 3 at the front end pushes the shock absorbing material 1 backward, and the rear end. When the bolt 3 of the portion presses the impact absorbing material 1 forward, shearing of the impact absorbing material 1 is induced between the bolt 3 at the front end portion and the bolt 3 at the rear end portion in the vehicle width direction.

When shearing is induced, the bolt 3 at the front end and the rear end of the impact absorber 1-1 at a position corresponding to the vehicle width direction enter the side member 9. The front end portion of the shock absorbing material 1-1 is pushed apart by the bolt 3 at the front end portion, and the compression portion 15 in the vehicle width direction is formed in a narrow space between the bolts 3 at the front end portion.

On the other hand, the front end portion of the impact absorbing material 1-2 at the position corresponding to the bolt 3 at the rear end portion in the vehicle width direction enters the bumper reinforce 11a toward the opening 111. The rear end portion of the shock absorbing material 1-2 is pushed apart by the bolt 3 at the rear end portion, and the compression portion 15 in the vehicle width direction is formed in the narrow space between the bolt 3 and the side member 9.

Also in the fifth embodiment, the compression portion 15 is configured by arranging the bolt 3 at the rear end portion close to the side surface of the shock absorbing material 1 and arranging the two adjacent bolts 3 at the front end portion close to each other. A high impact absorption effect can be obtained by the formation of. This also applies when a bolt 3a having a circular cross section is used. In this case, the position of the bolt 3a at the front end may be determined by the above equation (2'), that is, the equation (2).

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person skilled in the art can come up with various modified examples or modified examples within the scope of the technical idea disclosed in the present application, and these also naturally belong to the technical scope of the present invention. Understood.

For example, in each of the above embodiments, a shock absorbing mechanism is installed between the bumper reinforce and the side member of the vehicle 10, but the shock absorbing mechanism transmits the load to the load receiving member that receives the load at the time of collision in the vehicle 10. It may be provided between the members to be transmitted, and is not limited to the one provided between the bumper reinforce and the side member. For example, for the purpose of reducing the collision load at the time of a collision on the vehicle side, it may be provided between the body body on the side of the vehicle and the battery case inside the vehicle. Further, the type of the vehicle 10 is not particularly limited.

1, 1-1, 1-2: Impact absorber 2, 2', 2a, 2b, 2c, 2c', 2d: Impact absorption mechanism 3, 3a: Bolt 4: Nut 5: Flat surface portion 6: Concave surface portion 9: Side member 10: Vehicle 11, 11a: Bumper reinforcement 15, 15a: Compression part L: Cross-section center line La: Line segment X ₁ , X ₂ : Distance

Claims (6)

It is a shock absorbing mechanism for reducing the collision load applied to the vehicle.
A load receiving member that receives a collision load and a transmitted member to which the collision load is transmitted from the load receiving member are provided.
A wooden columnar shock absorber whose one end in the axial direction of the member is inserted into the internal space of the load receiving member and one of the members to be transmitted,
A first connecting material that is connected to the one member and presses the impact absorbing material in the event of a collision.
Equipped with
At the time of a collision, the impact absorbing material is pushed by the first connecting material, and enters the space on the side of the impact absorbing material in the direction orthogonal to the member axis when viewed from the first connecting material.
The width of the first connecting member along the member axis orthogonal direction is 2D ₁ , and the flat surface portion or concave portion of the first connecting member facing the other member side of the load receiving member and the transmitted member. With a width of 2C ₁
The distance between the cross-sectional center line in the axial direction of the member passing through the center of the cross section along the axial direction of the member of the first connecting material and the side surface of the shock absorbing material closer to the first connecting member. X ₁ is
X ₁ ≤ {D _1- (1-ε) C ₁ } / ε
Determined by
In the stress-strain distribution showing the relationship between stress and strain when the shock absorber is compressed in the direction perpendicular to the member axis, ε exceeds the elastic deformation range of the shock absorber and the rigidity of the shock absorber decreases. A shock absorbing mechanism characterized by having a strain value corresponding to a strain hardening region in which the rigidity of the shock absorbing material increases again. It is a shock absorbing mechanism for reducing the collision load applied to the vehicle.
A load receiving member that receives a collision load and a transmitted member to which the collision load is transmitted from the load receiving member are provided.
A wooden columnar shock absorber whose one end in the axial direction of the member is inserted into the internal space of the load receiving member and one of the members to be transmitted,
A plurality of first connecting members that are connected to the one member and press the impact absorbing material in the event of a collision.
Equipped with
At the time of a collision, the impact absorbing material is pushed by the first connecting material, and enters the space on the side of the impact absorbing material in the direction orthogonal to the member axis when viewed from the first connecting material.
The width of the first connecting member along the member axis orthogonal direction is 2D ₁ , and the flat surface portion or concave portion of the first connecting member facing the other member side of the load receiving member and the transmitted member. With a width of 2C ₁
A line in the axial direction of the member that bisects between the center line of the cross section in the axial direction of the member passing through the center of the cross section of the first connecting member along the axial direction of the member and the adjacent first connecting member. The distance X ₁ between the minutes is
X ₁ ≤ {D _1- (1-ε) C ₁ } / ε
Determined by
In the stress-strain distribution showing the relationship between stress and strain when the shock absorber is compressed in the direction perpendicular to the member axis, ε exceeds the elastic deformation range of the shock absorber and the rigidity of the shock absorber decreases. A shock absorbing mechanism characterized by having a strain value corresponding to a strain hardening region in which the rigidity of the shock absorbing material rises again. The cross section of the first connecting material is substantially circular, and the distance X ₁ is X ₁ ≤ D ₁ / ε with C ₁ = 0.
The shock absorbing mechanism according to claim 1 or 2, wherein the shock absorbing mechanism is defined by the above. The shock absorbing mechanism according to any one of claims 1 to 3, wherein the first connecting material is abutted against an end surface of the shock absorbing material. The shock absorbing mechanism according to any one of claims 1 to 3, wherein the first connecting material penetrates the shock absorbing material. The other end of the shock absorber in the axial direction of the member is inserted into the internal space of the other member.
Further comprising a plurality of second connecting members that are coupled to the other member and press the impact absorbing material in the event of a collision.
The first and second connecting members are arranged at different positions when viewed from the member axial direction.
At the time of a collision, the impact absorbing material is pushed by the second connecting material, and enters the space on the side orthogonal to the member axis when viewed from the second connecting material.
The width of the second connecting member along the member axis orthogonal direction is 2D ₂ , and the width of the flat surface portion or the concave surface portion of the second connecting member facing the one member side is 2C ₂ .
A line in the axial direction of the member that bisects between the center line of the cross section in the axial direction of the member passing through the center of the cross section of the second connecting member along the axial direction of the member and the adjacent second connecting member. The distance X ₂ between the minutes is
X ₂ ≤ {D _2- (1-ε) C ₂ } / ε
The shock absorbing mechanism according to any one of claims 1 to 5, wherein the shock absorbing mechanism is defined by the above-mentioned method.

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